Eli Lilly has reported that its experimental next-generation obesity medicine, retatrutide, performed better than Novo Nordisk’s Ozempic at controlling blood sugar. The company also said the drug produced more than twice the weight loss in a diabetes study, announcing the results on Wednesday.
The findings strengthen the case that retatrutide could drive Lilly’s next phase of growth, which analysts expect to follow the success of Zepbound and Mounjaro. Earlier studies had already shown weight loss at a level comparable to bariatric surgery in people with obesity, a result that could make it the most powerful drug in the fast-growing market.
How the head-to-head trial was designed
Retatrutide is taken once weekly and acts on three hormone receptors: GLP-1, GIP and glucagon. Drugs of this kind are expected to produce bigger weight loss than earlier generations by reducing appetite, improving blood sugar control and increasing calorie burning.
The trial compared 9 mg and 12 mg doses of retatrutide with a 2 mg dose of Ozempic. Lilly said it used that Ozempic dose because it is the highest approved dose available.
Blood sugar and weight loss results at 80 weeks
In the late-stage study, both retatrutide doses lowered A1C, a measure of blood sugar over time, by an average of 2.2%. Ozempic reduced it by 1.8% over the same 80 weeks. Patients on the higher retatrutide dose lost 20.9% of their weight, compared with 9.4% on Ozempic.
Citi analyst Geoffrey Meacham said the data reaffirmed the drug’s differentiated efficacy in weight and glycemic control. He described it as a key long-term cardiometabolic growth driver. Retatrutide also delivered larger improvements than Ozempic in certain cardiovascular risk factors.
Side effects and plans for approval
The most common side effects were gastrointestinal, including nausea, vomiting and diarrhea. About 7.9% of patients on the highest retatrutide dose stopped treatment, compared with 2.7% in the Ozempic group.
Lilly plans to seek US approval for retatrutide next year and will present detailed results at a future medical meeting. A separate late-stage study is testing the drug against tirzepatide, the active ingredient in Zepbound, in adults with obesity, with or without type 2 diabetes.
